N62 4.8 Oil Thermostat Gasket Leak (2007 X5)

[Xor]

Originally Posted by Entropy

Well, I was successful. 7.5 hours. Not a fun job. No draining of cooling or P/S system.

Jealous here, so fast! Good job!

Any issues? Anything was done different? Tips for society?

[Entropy]

Originally Posted by Xor

Jealous here, so fast! Good job!

Any issues? Anything was done different? Tips for society?

No issues, other than I forgot to DISCONNECT THE BATTERY before taking the alternator out!... Doh! It arced on to a hose crimp fitting as I was rotating it. Luckily no damage done... just an oh-$hit moment.

I will add to the steps-list we already have going:

1. Park and jack up front of vehicle.

2. Remove left front wheel.

2.5. Disconnect the negative terminal cable from the battery.

3. Remove the front-half of the plastic wheelwell liner (it's split into two pieces) and lower plastic pieces as well. You will have to knock out the plastic rivets that hold the fender flare on. This can be done with a punch and a hammer. Hammer the center of the rivet in, which allows the rivets to be pulled out. Remove the fender flare and then remove the front-half of the wheelwell liner.

4. Remove the intake components, support beam above the radiator, electric fan (note that the driver-side tab is hinged, allowing it to fold back onto itself so it can slip past the upper radiator hose).

5. Remove serpentine belt, idler pulley, and tensioner.

6. Remove alternator (I also removed the two bolts holding the P/S pump, giving me a bit more room).

7. Take note of the position of the alternator guide nut. You will want to install the alternator with that nut in the same position.

8. Remove oil cooler lines from thermostat assembly (this can be done with long extensions from the wheelwell)

9. Remove the three bolts holding the thermostat to the block. I was able to remove the top bolt and forward-most bolt from the wheelwell. The rear-lower bolt I had to do from the engine bay.

10. Take out the thermostat assembly, clean it, replace gasket. Also replace the O-rings on the oil cooler lines. I used a pick-tool to get all of the old gaskets and O-rings off.

Whatever you do, be extremely careful with the torx-head bolts BMW uses. There is very little socket engagement and they can round-off easily. I purchased new bolts for re-installation (not necessary, but advised). Note that I didn't touch any power-steering or engine coolant lines... no draining necessary.

This would also be a good time to do the front differential fluid, since it is exposed.